Project Summary Bacterial resistance has reached alarming levels in the US and other parts of the world in the past decade. The increase in bacterial infection with drug-resistant (DR) pathogens are resulting in increasing healthcare costs and a decline in positive clinical outcomes. Serious infections leading to sepsis remain a public health concern. In the United States alone, approximately 750,000 patients develop sepsis, which claims 250,000 lives every year with treatment failures often associated with multidrug resistance (MDR) bacterial pathogens as well as the complex pathophysiology of the disease. New therapies for controlling these DR pathogen-induced respiratory infections are urgently needed because: (a) the mortality rate among infected individuals requiring hospitalization remains very high; and (b) overuse of antibiotics has resulted in continuing emergence of additional MDR strains. Our long-term goal is to develop an effective, well tolerated antimicrobial peptide therapeutic to MDR pathogens -specifically the MDR Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp (ESKAPE) pathogens determined to be critical and high priority by the CDC and WHO. There is thus a dire need to develop novel antimicrobial compounds that have a broad spectrum of activity against both Gram-positive and Gram-negative bacteria, yet at the same time, are well tolerated with a low propensity to select for resistant strains of bacteria. This proposal seeks to develop computationally engineered synthetic antimicrobial peptides derived from a normal human protein with very low toxicity but broad-spectrum activity against MDR clinical bacterial isolates. Our lead therapeutic, CM-YPD1, has been validated in vitro and in vivo to have strong efficacy, stability, and safety and acts within minutes. Our multidisciplinary team brings together a unique combination of expertise and technology that will permit the development of a drug that can be used to treat a broad array of MDR bacterial infections.